Improvement in rock-drills



E. J. WILLIAMS. Rook-Drill.

Patented Nov. 11 I879.

UNITED STATES PATENT OFFICE.

EDWARD J. WILLIAMS, OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONE-HALF HISRIGHT TO LEVERETT A. PRATT, OF SAME PLACE.

IMPROVEMENT IN ROCK-DRILLS.

Specification forming part of Letters Patent No. 221,646, dated November11, 1879 application filed August 20, 1879.

To all whom it may concern:

Be it known that I, EDWARDQJ. WILLIAMS, of St. Louis, Missouri, havemade a new and useful Improvement'in Rock-Drills, of which the followingis a full, clear, and exact description, reference being had to theannexed drawings, making part of this specification, in which- Figure lis a side elevation of a portion of a drill having the improvement; Fig.2, a similar view, the parts being detached; Fig. 3, a side elevation,taken at right angles to that of Fig. 1; and Figs. 4; and 5, viewsillustrating the working of the drill, being vertical sections takenthrough rock, the former showing the drill-hole incomplete, and thelatter showing the hole as finished with the improved drill.

Similar letters denote the same parts.

The aim of this invention is to provide an improved means for enlargingthe diameter of a drill-hole at the bottom thereof and it consists inmaking the drill in two parts, which are jointed together, the lowerpart being that portion of the drill immediately connected with andsupporting the cutting-edge of the drill, and having the cutting-edge atone side of or eccentric to the longitudinal axis of the drill.

The shape and mode of joining the parts, being essential features of theinvention, are

more particularly described as follows:

Referring to the drawings, A represents a rock-drill, which, saving asmodified by the present improvement, may beof the usual description.lnstead of being in one piece the drill is made in two parts, a and b.The part b constitutes the lower end of the drill, having thecutting-edge 0 thereon. The latter is at the side of the center of thedrill, and is formed by means of the two bevels d d, as

. shown, and at a point about midway'between the center and the side 0of the part b.

The parts a and b are jointed together, one of the parts, say a, beingprovided with a tenon, a, which engages with a knuckle, b b, upon thepart b. The lower end of the tenon is rounded as well as the upper endof the knuckle b b, and the parts are so shaped as to cause the tenon,when the drill is in use, to

bear against and turn upon the bottom of the recess between the twoparts of the knuckle, and the knuckle to bear against and turn upon theshoulders at a on either side of the tenon, the recess and also theshoulder being rounded to fit the tenon and knuckle, respectively, for,although a pintle, f, is used to connect the parts a and b and toprevent the latter from dropping off the former, no strain in using thedrill is allowed to come upon it, and the pintle'hole f is elongated toprovide for this. This construction enables the parts a and b to turnupon each other, and the parts are arranged for the plane of the turningto be at right angles to the cutting-edge c, and as indicated by thedotted lines in Fig. 1.

In practice a hole, 9, Figs. 4, 5, is drilled in the ordinary way and tothe desired depth. The improved drill A is then inserted and thedrilling continued. Owing to the position of the cutting-edge 0 upon thepart b the latter turns upon the former, as indicated in Fig. 1, causingthe hole 9 to be chambered, as shown at 9, Fig. 5. The drill is turnedaround as in ordinary drilling.

The movement of the part 1) upon the part a is limited by the shoulderit coming against the part a at h, or in other suitable manner.

I am aware that drills have been divided and that the cutting portion ofthe drill has been ointed to the drill-head. I therefore do not claimsuch broadly, as my improvement relates to the particular form of cutterand mode of jointing it to the drill-head shown and described; and

I claim- The combination of the part a, having the rounded shoulders aa, and the rounded tenon at, having the elongated perforation f, thepart b, having the rounded knuckle b b, and the edge 0, arranged, asdescribed, at the side of the center of the drill and at right angles tothe plane in which the part b turns, and the pin f, substantially as andfor the purposes set forth.

EDWARD J. WILLIAMS.

Witnesses CHAS. D. MOODY, CHARLES PIGKLES.

